In certain applications, mobile heating systems are utilized to heat liquids, such as water or water-based solutions, collectively termed process water, for distribution through tanks and reservoirs. For example, one such application commonly known as a hydraulic fracturing or “frac job”, involves injecting large quantities of a heated aqueous solution into a subterranean formation of an oil or gas well to hydraulically fracture the formation to release the oil or gas. Such frac jobs are normally used to initiate production in low permeability reservoirs, or to re-stimulate production in older producing wells. The heated water is typically combined with and acts to dissolve a mixture of chemical additives, propants (light sand) and a guar gel, that helps carry the sand down into the well. This tracing liquid solution is injected into a well at a high flow rate and pressure to break up the formation, and help the gas or oil flow towards the surface.
Hydraulic fracturing is performed at remote well sites and usually requires a short period of time to complete. Consequently, the construction of a permanent heating facility at the site is not cost effective, accordingly a mobile heating system employing one or more heat exchangers is commonly used. Such known mobile heating systems need to be designed mindful of current US government safety regulations which provide that open flame heating of the aqueous solution cannot take place in the immediate vicinity of the well. While safety concerns are of overriding importance, compliance with such “no flame” regulations requires additional time and expense to provide the requisite liquid heating. As a result, known mobile heating systems are found to provide less than homogenous temperature distribution of heated water solutions through tanks and reservoirs, and a less than desired pumping behavior throughout the system. Accordingly, improvements in providing a flameless, self-contained mobile system for heating supply fluids, and particularly water and water-based liquids, are highly desirable.